Comprehensive assessment of the results of surgical treatment of severe forms of idiopathic scoliosis with a primary thoracic curve

Objective. To identify main negative factors influencing the comprehensive assessment of the results of surgical treatment of severe idiopathic scoliosis with a primary thoracic curve. Material and Methods. A total of 288 patients were operated on for idiopathic scoliosis with main thoracic curve (Lenke types 1, 2, 3 and 4) measuring 93.0° [85.0°; 105.0°] in 1999–2019. Out of them, 154 patients had the lumbar countercurvature of 62.0° [53.0°; 72.5°]. All patients were operated on using posterior segmental instrumentation with hook fixation, hybrid (hook fixation in the thoracic and transpedicular one in the lumbar and thoracolumbar spine) and transpedicular fixation. The median age of patients at the time of surgery was 15.0 [13.0; 17.0] years, and the median period of postoperative follow-up – 4.3 [3.0; 6.2] years. Clinical and radiological data in the preoperative, postoperative and in long-term postoperative periods, and data of the SRS-24 survey were analyzed. The threshold values of eight clinical parameters were evaluated based on their excess of reference parameters of the physiological norm and data substantiated by previously conducted studies. Results. The residual thoracic curvature of more than 70° was detected in 32 (11.1%) patients, thoracic kyphosis over 60° – in 22 (7.6%), shoulder girdle tilt more than 5 ° – in 39 (13.5%), correction less than 50% – in 108 (37.5%), clinical frontal imbalance – in 49 (17.0%), hypokyphosis – in 79 (27.4%), hypolordosis – in 37 (12.8%), and total SRS-24 score less than 80 points – in 7 (2.4%) patients. Excellent results were stated in 123 (42.7%) patients, good - in 118 (41%), including 42 (35.6%) with one or more significant negative factors; satisfactory results were stated in 44 (15.3%) patients, including 35 (79.5%) with critical negative factors. Unsatisfactory results were noted in 3 (1.0%) patients. Conclusion. Identification of statistically significant differences in 398 parameters made it possible to reveal eight negative factors that affect the outcome of treatment of severe thoracic scoliosis, and to determine their threshold values. Three critical negative factors have the greatest impact on the result of surgical treatment: the residual thoracic scoliotic curve more than 70°, thoracic hyperkyphosis more than 60° and shoulder girdle tilt more than 5°.